Full control of electric and magnetic light-matter interactions through a nanomirror on a near-field tip

Light-matter interactions are often considered governed by the electric optical field only, leaving aside the magnetic component of light. However, the magnetic part plays a determining role in many optical processes, from light and chiral-matter interactions and photon-avalanching to forbidden photochemistry, making the manipulation of magnetic processes extremely relevant. Here, by creating a standing wave using a metallic nanomirror, we manipulate the spatial distributions of electric and magnetic fields and their associated local densities of states, allowing selective control of the excitation and emission of electric and magnetic dipolar transitions. This control allows us to image, in 3D, the electric and magnetic nodes and anti-nodes of the fields' interference patterns. It also enables us to enhance specifically photoluminescence from quantum emitters excited only by the magnetic field, and to manipulate their spontaneous emission by acting on the excitation fields solely, demonstrating full control of magnetic and electric light-matter interactions. (c) 2023 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement